Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
, 20 (1), 225-261
eCollection

Synthesis and Modelling of the Mechanical Properties of Ag, Au and Cu Nanowires

Affiliations
Review

Synthesis and Modelling of the Mechanical Properties of Ag, Au and Cu Nanowires

Nurul Akmal Che Lah et al. Sci Technol Adv Mater.

Abstract

The recent interest to nanotechnology aims not only at device miniaturisation, but also at understanding the effects of quantised structure in materials of reduced dimensions, which exhibit different properties from their bulk counterparts. In particular, quantised metal nanowires made of silver, gold or copper have attracted much attention owing to their unique intrinsic and extrinsic length-dependent mechanical properties. Here we review the current state of art and developments in these nanowires from synthesis to mechanical properties, which make them leading contenders for next-generation nanoelectromechanical systems. We also present theories of interatomic interaction in metallic nanowires, as well as challenges in their synthesis and simulation.

Keywords: 10 Engineering and Structural materials; 105 Low-Dimension (1D/2D) materials; 106 Metallic materials; 400 Modeling / Simulations; 500 Characterization, Nanomechanical Characterization; Coinage metal nanowires; molecular modelling; nanotechnology; synthesis method.

Figures

None
None
Figure 1.
Figure 1.
(a) 1D metal nanostructures comprise nanowires, nanobelts, nanorods and nanotubes [26–28]. (b) A collection of experimental measurements and predictions regarding the yield strength of pure Au nanostructures as a function of lateral specimen dimension. Smaller specimens tend to be stronger. At nanoscale length, Au nanowires demonstrate excellent yield strength compared to single-atom chains that typically undergo atomic separation. The relative sizes of Au atom and human hair are included for comparisons [30]. (c) An example of stress vs strain plot of Ag nanowire system at different strain rates [31]. (Reproduced from [26] by permission of the Nature Publishing Group [27], by permission of the Royal Society of Chemistry [28], Copyright (2013) American Chemical Society [30], Copyright (2004) American Chemical Society, reprinted with permission from [31] copyright (2016) American Chemical Society).
Figure 1.
Figure 1.
(a) 1D metal nanostructures comprise nanowires, nanobelts, nanorods and nanotubes [26–28]. (b) A collection of experimental measurements and predictions regarding the yield strength of pure Au nanostructures as a function of lateral specimen dimension. Smaller specimens tend to be stronger. At nanoscale length, Au nanowires demonstrate excellent yield strength compared to single-atom chains that typically undergo atomic separation. The relative sizes of Au atom and human hair are included for comparisons [30]. (c) An example of stress vs strain plot of Ag nanowire system at different strain rates [31]. (Reproduced from [26] by permission of the Nature Publishing Group [27], by permission of the Royal Society of Chemistry [28], Copyright (2013) American Chemical Society [30], Copyright (2004) American Chemical Society, reprinted with permission from [31] copyright (2016) American Chemical Society).
Scheme 1.
Scheme 1.
Synthesis, nanomechanical characterisation and simulation of coinage metal nanowires presented in this review (reprinted with permissions from [34] licensed under a Creative Commons Attribution 4.0 International License, with permission from [35] licensed under a Creative Commons Attribution-Non Commercial-Share Alike 3.0 Unported License, with permission from [36] Copyright (2011) American Chemical Society, with permissions from [37,38] under IOP Publishing [39,40], are licensed under a Creative Commons Attribution 4.0 International License, reproduced from [41] with permission from The Royal Society of Chemistry).
Scheme 1.
Scheme 1.
Synthesis, nanomechanical characterisation and simulation of coinage metal nanowires presented in this review (reprinted with permissions from [34] licensed under a Creative Commons Attribution 4.0 International License, with permission from [35] licensed under a Creative Commons Attribution-Non Commercial-Share Alike 3.0 Unported License, with permission from [36] Copyright (2011) American Chemical Society, with permissions from [37,38] under IOP Publishing [39,40], are licensed under a Creative Commons Attribution 4.0 International License, reproduced from [41] with permission from The Royal Society of Chemistry).
Figure 2.
Figure 2.
(a) Top: Schematic of Ag ions complexation with PVP chains. PVP owns polyvinyl skeleton structure with the strong pyrrolidone ring polar group. The polar groups (N-C = O) of the PVP chains interact with silver ions and form a coordinating complex. The illustration of 1D Ag-PVP coordination condition shows that high molecular weight (MW) PVP has relatively large silver ions coordinated along the long chain [72]. Bottom: Schematic of the formation of fcc single-crystalline subunits from fivefold-twinned nanowires [75]. (b) Schematic of the role of Cu salt in the surfactant-assisted soft chemistry process. The presence of molecular oxygen during the early stage of seeds formation allows absorbance and dissociation on the surface of the seeds [80]. (Reprinted with permission from [72] under Creative Commons Attribution License [75], copyright (2013) American Chemical Society and reproduced from [80] with permission from The Royal Society Chemistry).
Figure 2.
Figure 2.
(a) Top: Schematic of Ag ions complexation with PVP chains. PVP owns polyvinyl skeleton structure with the strong pyrrolidone ring polar group. The polar groups (N-C = O) of the PVP chains interact with silver ions and form a coordinating complex. The illustration of 1D Ag-PVP coordination condition shows that high molecular weight (MW) PVP has relatively large silver ions coordinated along the long chain [72]. Bottom: Schematic of the formation of fcc single-crystalline subunits from fivefold-twinned nanowires [75]. (b) Schematic of the role of Cu salt in the surfactant-assisted soft chemistry process. The presence of molecular oxygen during the early stage of seeds formation allows absorbance and dissociation on the surface of the seeds [80]. (Reprinted with permission from [72] under Creative Commons Attribution License [75], copyright (2013) American Chemical Society and reproduced from [80] with permission from The Royal Society Chemistry).
Figure 3.
Figure 3.
(a) Schematic of two soft-template methods of growing Ag nanowires. These two conventional procedures consist of polymerisation-condensation of inorganic (mark with (i)) and inorganic precursor incorporation that form the organic-inorganic phase as a product (mark with (ii)) [107]. (b) Schematic illustration of Ag nanowires inside polystyrene nanotube as a soft template and anodic alumina membrane as a solid template [113]. (c) The schematic illustration of the concept of nanowires synthesis within a composite. Keilbach et al. [108] chose the AAM pores as a template for the columnar nanowires. The columnar will be then used as the mould for the electrodeposition process for nanowires. (Reproduced with permission from [107] Copyright (2007) American Chemical Society, reproduced from [113] with permission from Nature Publishing Group, adapted with permission from [108] copyright (2010) American Chemical Society).
Figure 3.
Figure 3.
(a) Schematic of two soft-template methods of growing Ag nanowires. These two conventional procedures consist of polymerisation-condensation of inorganic (mark with (i)) and inorganic precursor incorporation that form the organic-inorganic phase as a product (mark with (ii)) [107]. (b) Schematic illustration of Ag nanowires inside polystyrene nanotube as a soft template and anodic alumina membrane as a solid template [113]. (c) The schematic illustration of the concept of nanowires synthesis within a composite. Keilbach et al. [108] chose the AAM pores as a template for the columnar nanowires. The columnar will be then used as the mould for the electrodeposition process for nanowires. (Reproduced with permission from [107] Copyright (2007) American Chemical Society, reproduced from [113] with permission from Nature Publishing Group, adapted with permission from [108] copyright (2010) American Chemical Society).
Figure 4.
Figure 4.
Schematic illustration from (a) on short Ag nanowires growth using PVD method deposited on the Si substrate [185] and (b) on the concept of the twin boundaries arrangement, coloured in brown with (i) single crystal nanowires without twin boundaries, (ii) horizontal, (iii) inclined and (iv) fivefold vertical twin boundaries [200] (adapted with permission from [185] licensed under a Creative Commons Attribution 4.0 International License and [200] copyright (2015) American Chemical Society).
Figure 4.
Figure 4.
Schematic illustration from (a) on short Ag nanowires growth using PVD method deposited on the Si substrate [185] and (b) on the concept of the twin boundaries arrangement, coloured in brown with (i) single crystal nanowires without twin boundaries, (ii) horizontal, (iii) inclined and (iv) fivefold vertical twin boundaries [200] (adapted with permission from [185] licensed under a Creative Commons Attribution 4.0 International License and [200] copyright (2015) American Chemical Society).
Figure 5.
Figure 5.
(a) Experimental setup of AFM cantilevers on the SEM stage [225]. The cantilever is mounted on a metal block of screw nut using a stable glue, providing excellent electrical contact with the close-up on the fracture area of the wire. (b) TEM images are used to monitor quantitative tensile tests before, right before and after breaking 20 nm diameter Au nanowires [4]. (c) TEM nanoindentation holder with the sample mounted on the metal rod. The image is originally courtesy of the Model 2030 Ultra-Narrow Gap Tomography Holder from Eden Instruments (http://www.eden-instruments.com). (d) Reversible compressive deformation through twinning and de-twinning transition during cyclic tension-compression. The first tensile loading near the tensile grip (image 1 to 2) and eliminated entirely by de-twinning during compression (images 2 and 3). The successive nucleation and extension of parallel nanotwins along the same slip area (images 4 and 5) with the accommodation of de-twinning during subsequent compression (image 6) [4]. (Reproduced from [225] with permission from IOP Publishing and reproduced from [4] with permission from Nature Publishing Group).
Figure 5.
Figure 5.
(a) Experimental setup of AFM cantilevers on the SEM stage [225]. The cantilever is mounted on a metal block of screw nut using a stable glue, providing excellent electrical contact with the close-up on the fracture area of the wire. (b) TEM images are used to monitor quantitative tensile tests before, right before and after breaking 20 nm diameter Au nanowires [4]. (c) TEM nanoindentation holder with the sample mounted on the metal rod. The image is originally courtesy of the Model 2030 Ultra-Narrow Gap Tomography Holder from Eden Instruments (http://www.eden-instruments.com). (d) Reversible compressive deformation through twinning and de-twinning transition during cyclic tension-compression. The first tensile loading near the tensile grip (image 1 to 2) and eliminated entirely by de-twinning during compression (images 2 and 3). The successive nucleation and extension of parallel nanotwins along the same slip area (images 4 and 5) with the accommodation of de-twinning during subsequent compression (image 6) [4]. (Reproduced from [225] with permission from IOP Publishing and reproduced from [4] with permission from Nature Publishing Group).
Figure 6.
Figure 6.
(a) The in situ tensile test of Ag nanowires using SEM with the scale bar of 200 nm [3]. (b) The low magnification of TEM image on the sample area of the nanowire bridge between the actuator and the load sensor with the scale bar of 500 nm [3]. (c) The stress-strain curves of penta-twinned Ag nanowires with a diameter of 120 nm. The relaxation and recovery states took 15 min to complete [3]. (d) Schematic of a bimetallic Ni-Au nanowire with the Au segment (yellow) attached to an amino-functionalised glass slide [236]. (e) Nanowire cross-sections indicate the acceptable indentation region (left) and the contact depth, hc during deformation (right) [236]. (f) AFM images and line profiles before and after the indentation test for both Au and Ni nanowires segments [236]. (Adapted from [3] with permission from Nature Publishing Group and reproduced from [236] with permission from Elsevier).
Figure 6.
Figure 6.
(a) The in situ tensile test of Ag nanowires using SEM with the scale bar of 200 nm [3]. (b) The low magnification of TEM image on the sample area of the nanowire bridge between the actuator and the load sensor with the scale bar of 500 nm [3]. (c) The stress-strain curves of penta-twinned Ag nanowires with a diameter of 120 nm. The relaxation and recovery states took 15 min to complete [3]. (d) Schematic of a bimetallic Ni-Au nanowire with the Au segment (yellow) attached to an amino-functionalised glass slide [236]. (e) Nanowire cross-sections indicate the acceptable indentation region (left) and the contact depth, hc during deformation (right) [236]. (f) AFM images and line profiles before and after the indentation test for both Au and Ni nanowires segments [236]. (Adapted from [3] with permission from Nature Publishing Group and reproduced from [236] with permission from Elsevier).
Figure 7.
Figure 7.
(a) The AFM images of a 23.6 nm Ag nanowire under the tapping mode test before and after the brittle failure occurred with the scale bar of 250 nm [241]. (b) The Young’s modulus plot as a function of Ag nanowire radius. The modulus remains the same before (circle) and after (star) the thermal annealing process [241]. (c) The plot of the elastic modulus vs diameter of the Ag nanowires with the nanowire diameter assigned from the fixed beam model (*), simple beam model (**) and simple fixed beam model (***) [242]. (d) In situ micro-diffraction pattern sequence for the Au 111 and Si 011 Laue spots evolution during the bending test [243] with (e) the bending angle plot as a function of the AFM cantilever movement [243]. (f) The snapshots of strain exerted on the nanowires [248]. (Adapted with permission from [241] copyright (2006) American Chemical Society, reproduced from [242] with permission by AIP Publishing LLC, adapted with permission from [243] under the terms of the Creative Commons Attribution Licence and adapted from [248] with permission from Nature Publishing Group).
Figure 7.
Figure 7.
(a) The AFM images of a 23.6 nm Ag nanowire under the tapping mode test before and after the brittle failure occurred with the scale bar of 250 nm [241]. (b) The Young’s modulus plot as a function of Ag nanowire radius. The modulus remains the same before (circle) and after (star) the thermal annealing process [241]. (c) The plot of the elastic modulus vs diameter of the Ag nanowires with the nanowire diameter assigned from the fixed beam model (*), simple beam model (**) and simple fixed beam model (***) [242]. (d) In situ micro-diffraction pattern sequence for the Au 111 and Si 011 Laue spots evolution during the bending test [243] with (e) the bending angle plot as a function of the AFM cantilever movement [243]. (f) The snapshots of strain exerted on the nanowires [248]. (Adapted with permission from [241] copyright (2006) American Chemical Society, reproduced from [242] with permission by AIP Publishing LLC, adapted with permission from [243] under the terms of the Creative Commons Attribution Licence and adapted from [248] with permission from Nature Publishing Group).
Figure 8.
Figure 8.
(a) The atomic modelling of Ag nanowire with a diameter of 15 nm under tensile stress before the deformation corresponds to the AFM image after the nanoindentation test. The tensile stress-strain plot shows prediction results from atomistic simulations [266]. (b) The multishell nanowire with the yield strength takes place at the local tensile fracture in the atomic junction [30]. (c) The tensile yield of the metal nanowires with the coloured atoms is defined according to the slip vector, and only the atoms that have slipped are shown in a to d, while all of the present atoms are shown in e [268]. (d) Slip during the yielding and twinning during deformation of the Au nanowire. The left snapshot shows all atoms, while the right snapshot presents only atoms on the slip planes. The atoms are coloured based on the magnitude of the potential energy [267]. (Adapted from [266] with permission copyright (2008) by the American Physical Society, adapted with permission from [30] copyright (2004) American Chemical Society, reproduced from [268] with permission from Elsevier, reproduced from [267] with permission from Springer).
Figure 8.
Figure 8.
(a) The atomic modelling of Ag nanowire with a diameter of 15 nm under tensile stress before the deformation corresponds to the AFM image after the nanoindentation test. The tensile stress-strain plot shows prediction results from atomistic simulations [266]. (b) The multishell nanowire with the yield strength takes place at the local tensile fracture in the atomic junction [30]. (c) The tensile yield of the metal nanowires with the coloured atoms is defined according to the slip vector, and only the atoms that have slipped are shown in a to d, while all of the present atoms are shown in e [268]. (d) Slip during the yielding and twinning during deformation of the Au nanowire. The left snapshot shows all atoms, while the right snapshot presents only atoms on the slip planes. The atoms are coloured based on the magnitude of the potential energy [267]. (Adapted from [266] with permission copyright (2008) by the American Physical Society, adapted with permission from [30] copyright (2004) American Chemical Society, reproduced from [268] with permission from Elsevier, reproduced from [267] with permission from Springer).
Figure 9.
Figure 9.
(a) The atomic model of Ag nanowires for the evolution of dislocation and their microstructure changed under different applied strain. The coloured atoms are specified according to the CAN method with the yield strength and their effective surface elastic modulus of Ag nanowires as a function of the surface fraction [279]. (b) The effect of increasing temperature and engineering strain on Young’s modulus inelastic region [280]. (c) The stress relaxation and strain recovery of the metallic nanowires [3]. (d) The twinning and de-twinning processes with the growth of a twin under tension and de-twinning by reverse glide dislocation with the same Burgers vector [4]. (Reproduced from [279,280] with permissions from Elsevier, adapted from [4] with permission from Nature Publishing Group).
Figure 9.
Figure 9.
(a) The atomic model of Ag nanowires for the evolution of dislocation and their microstructure changed under different applied strain. The coloured atoms are specified according to the CAN method with the yield strength and their effective surface elastic modulus of Ag nanowires as a function of the surface fraction [279]. (b) The effect of increasing temperature and engineering strain on Young’s modulus inelastic region [280]. (c) The stress relaxation and strain recovery of the metallic nanowires [3]. (d) The twinning and de-twinning processes with the growth of a twin under tension and de-twinning by reverse glide dislocation with the same Burgers vector [4]. (Reproduced from [279,280] with permissions from Elsevier, adapted from [4] with permission from Nature Publishing Group).
Figure 10.
Figure 10.
(a) FEM of bending angle with and without geometric nonlinearities of Au nanowires as a function of the piezo movement. Both the position and size of the AFM tip and X-ray beam during the test are illustrated. The illustrations of the total displacement, the stress σyy along the wire and the volumetric strain for the gold based on the FEM simulation are presented accordingly [243]. (b) Radial stress shown in panel a and azimuthal stress in panel b demonstrate the axial symmetry of a stretched nanowire with a diameter and length of 6.66 nm [29]. (c) The meshing hexagonal cross-section FEM of nanowire specimen (left) and the diameter dependence of the effective Young’s modulus (right), which compares FEM and other models under prescribed stress [283]. (d) The SEM image of clamping nanowires with the comparison of finite element analysis (FEA) of nanowires against the experimental data and another simulation method [285]. (e) Displacement in various nanowire geometries (a – circular, b and c – hexagonal, d – pentagonal and e to f – rectangular) with the comparison of FEM results to the experimental data [287]. (Reproduced from [243] with permission under the terms of the Creative Commons Attribution Licence, reproduced from [29] with permission under AIP Publishing LLC, reproduced from Ref [283,285]. with permission from Elsevier and adapted from [287] with permission under the terms of the Creative Commons Attribution License).
Figure 10.
Figure 10.
(a) FEM of bending angle with and without geometric nonlinearities of Au nanowires as a function of the piezo movement. Both the position and size of the AFM tip and X-ray beam during the test are illustrated. The illustrations of the total displacement, the stress σyy along the wire and the volumetric strain for the gold based on the FEM simulation are presented accordingly [243]. (b) Radial stress shown in panel a and azimuthal stress in panel b demonstrate the axial symmetry of a stretched nanowire with a diameter and length of 6.66 nm [29]. (c) The meshing hexagonal cross-section FEM of nanowire specimen (left) and the diameter dependence of the effective Young’s modulus (right), which compares FEM and other models under prescribed stress [283]. (d) The SEM image of clamping nanowires with the comparison of finite element analysis (FEA) of nanowires against the experimental data and another simulation method [285]. (e) Displacement in various nanowire geometries (a – circular, b and c – hexagonal, d – pentagonal and e to f – rectangular) with the comparison of FEM results to the experimental data [287]. (Reproduced from [243] with permission under the terms of the Creative Commons Attribution Licence, reproduced from [29] with permission under AIP Publishing LLC, reproduced from Ref [283,285]. with permission from Elsevier and adapted from [287] with permission under the terms of the Creative Commons Attribution License).
Figure 11.
Figure 11.
(a) A 4 µm nanowire with various end charge shows the pair-longitudinal distribution function from MC simulation [290]. (b) Snapshot of a 256-atom Au nanowire, which broke in solvent and then reconnected, bridging a Au-BDT-Au junction at room temperature. The order is: i – breaking at Δz = 2.3 nm, ii – reconnecting at Δz = −0.5 nm and iii – reconnecting at Δz = −0.1 nm [291]. (Adapted with permission from [290] copyright (2010) American Chemical Society, reprinted with permission from [291] Copyright (2010) American Chemical Society).
Figure 11.
Figure 11.
(a) A 4 µm nanowire with various end charge shows the pair-longitudinal distribution function from MC simulation [290]. (b) Snapshot of a 256-atom Au nanowire, which broke in solvent and then reconnected, bridging a Au-BDT-Au junction at room temperature. The order is: i – breaking at Δz = 2.3 nm, ii – reconnecting at Δz = −0.5 nm and iii – reconnecting at Δz = −0.1 nm [291]. (Adapted with permission from [290] copyright (2010) American Chemical Society, reprinted with permission from [291] Copyright (2010) American Chemical Society).

Similar articles

See all similar articles

Cited by 1 article

References

    1. Cahn JW, Lärché F. Surface stress and the chemical equilibrium of small crystals-II. Solid particles embedded in a solid matrix. Acta Metall. 1982;30(1):51–56.
    1. Azizi A, Zou X, Ercius P, et al. Dislocation motion and grain boundary migration in two-dimensional tungsten disulphide. Nat Commun. 2014;5:4867. - PubMed
    1. Qin Q, Yin S, Cheng G, et al. Recoverable plasticity in penta-twinned metallic nanowires governed by dislocation nucleation and retraction. Nat Commun. 2015;6:5983. - PMC - PubMed
    1. Lee S, Im J, Yoo Y, et al. Reversible cyclic deformation mechanism of gold nanowires by twinning–detwinning transition evidenced from in situ TEM. Nat Commun. 2014;5:3033. - PubMed
    1. Wang YH, Xiong NN, Li ZL, et al. A comprehensive study of silver nanowires filled electrically conductive adhesives. J Mater Sci. 2015;26(10):7927–7935.

Grant support

This work was supported by the Universiti Malaysia Pahang [RDU 1703152]; Universiti Malaysia Pahang [RDU 161117].

LinkOut - more resources

Feedback